In the city, the Pennsylvania suburbs, South Jersey, and Delaware, a national record of 85,000 people volunteered in 1,300 service projects in the 17th annual event, according to Todd Bernstein, president of Global Citizen and founder and director of the Greater Philadelphia King Day of Service.
About 4,000 volunteers gathered at Girard, a tuition-free private boarding school for children in grades one through 12 that once barred black students.
On hand to mark the day, Vice President Biden said King himself once stood at the gates of the school in the Fairmount section, calling for equality.
"It's worth looking at how much progress we made," he said. Biden said everyone can improve this country by building on King's legacy: "The greatest thing you can do for another human being is understand what they are going through and then engage in one act of kindness."
Mayor Nutter also spoke, referencing recent gun violence and proclaiming, "Cease fire in this city!"
But the essence of Martin Luther King's Birthday is volunteerism, not elected officials at a microphone.
And citizens did much to bring that to life by engaging in scores of projects: Young people painted and cleaned elementary schools and recreation centers, volunteers created Valentine's Day cards for veterans convalescing in hospitals, and Olney residents distributed diapers to teenage parents.
Outside the city, the theme was much the same.
With the Comcast building in the background, several dozen Friends of the Cynwyd Heritage Trail, many with children, turned out to clear brush, yank out invasive vines, and remove debris from woods just off Belmont Avenue in Bala Cynwyd, Lower Merion.
The area is near the new Cynwyd Heritage Trail. It had been a dumping ground for contractors' debris, but it will someday be a meadow for native plants and species, the volunteers said.
Bundled up in parkas, wool hats, and gloves, many of the volunteers were students with a day off from classes.
Elaine Schmidt, 18, and Nora Choug, 22, both enrolled at Bryn Mawr College, gathered sticks and rubbish and carried them to a huge pile that will be removed later.
"I think it's a good day to get out and contribute," Schmidt said.
Nick Barnes Batista, 13, an eighth grader at Bala Cynwyd Middle School, was there helping his father, David Barnes, rip out dried-up kudzu.
As a cyclist, Batista is out on the trail a lot.
"I should help and give back, so I can go on it more," he said with a huge grin.
Eight miles away, in a warehouse overlooking West Conshohocken, several dozen students from the private Shipley School helped sort and inspect items for a nonprofit organization called Cradles to Crayons.
The group collects children's clothes, cleans and sorts them, adds new undergarments, books and school supplies, and makes up "kid packs" for those in need.
Henry Schoeffel, 10, a fourth grader from Berwyn, happily buzzed around, sorting and chatting.
"I love it," he said.
Sisters Ashleigh, 12, and Kaela Gundy, 15, of Lafayette Hill, said they felt lucky to attend a private school and wanted to help those less fortunate.
"I came here today to help pack up things and put them in order so someone can succeed with their life. It's like their life will change," Ashleigh Gundy said.
"We wanted to help others," said Kaela Gundy. "It's a day of service to honor Martin Luther King Jr."
It was also a day to contemplate the life of an extraordinary man.
On Monday, more than two dozen people ripped open the boarded-up door of a house in the Bergen Square neighborhood of Camden and started cleaning up the mess inside.
One of many similarly vacant homes with fire damage, 940 Newton Ave. looks unremarkable.
But some in the neighborhood say they believe King had lived at that house while he attended Crozer Theological Seminary in Upland in the late 1940s.
Historians cannot say for certain. But Heart of Camden, a nonprofit group that does redevelopment work in the city, nevertheless purchased the $4,000 in accumulated tax liens on the house.
The burned shell will be transformed into an office space for Young Urban Leaders, eight community-involved Camden residents. They plan to hold seminars and help city youth with college applications.
Once Heart of Camden receives the title for the property, it will turn it over to the Young Urban Leaders.
"It will be a shrine and inspiration to all of us," Msgr. Michael Doyle of Camden's Sacred Heart Church told a crowd at the site.
"This house reminds me a lot of Camden. . . . It has a strong foundation," but it needs to be fixed, said Sean Brown, a Camden school board member and founder of the Young Urban Leaders.
"Martin Luther King Day is a day to honor his legacy by doing service work around the country," Brown said. "We agreed it would be the perfect day to start restoring the house."
Contact staff writer Alfred Lubrano at 215-854-4969 or firstname.lastname@example.org.